They send a message to our government that we do not support what Israel is doing in Gaza. If our hands were perfectly clean then I would understand why you are asking but they are not, we have deployed military assets to the Mediterranean to support Israel and RAF transport planes are making regular trips between Cyprus and Tel Aviv, delivering who knows what.
https://www.gov.uk/government/news/prime-minister-deploys-uk-military-to-eastern-mediterranean-to-support-israel
I hope we're not supplying munitions or the UK Government could be in violation the Export Control Act 2002.
https://www.gov.uk/guidance/end-use-controls-applying-to-military-related-items
This control will only be invoked, and a licence application refused, where it is assessed that the export would be capable of having a ‘relevant consequence’.
This is as set out in the Schedule to the Export Control Act 2002, and described as:
a threat to the UK’s national security
having an adverse effect on peace, security or stability
an act threatening international peace and security
an act contravening the international law of armed conflict
an act of internal repression
an act that breaches human rights
an act of carrying out (or of acts which facilitate) acts of terrorism or serious crime
Polls show the majority of the UK population support a ceasefire.
And no I do not support antisemites attaching themselves to protests calling for peace and I do not support disruptive or intimidating behaviour. I do support people's right to peacefully protest.